Rolling guide apparatus

ABSTRACT

A rolling guide apparatus comprises a first slide member and second slide member. The first slide member includes a pair of wing portions and a connecting portion connecting the wing portions. First raceway grooves are formed on the wing portions, individually. Second raceway grooves are formed on the second slide member. Rolling elements are held under a pre-load between the raceway grooves. A residual compression stress region is created on the surface region of the first slide member. A worked portion is formed on the connecting portion. The worked portion serves to adjust the pre-load on the rolling elements by regulating the residual compression stress region by working to deform the connecting portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2000-189977, field Jun.23, 2000, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a rolling guide apparatus, suchas a linear guide apparatus or circular guide apparatus.

[0003] A rolling guide apparatus comprises a first slide memberincluding a pair of wing portions opposed to each other and a secondslide member capable of moving relatively to the first slide member. Aplurality of rolling elements, such as balls, are held between the wingportions of the first slide member and the second slide member.

[0004] For example, a linear guide apparatus includes a carriage as anexample of the first slide member and a rail as an example of the secondslide member. The carriage can relatively move in the axial direction(longitudinal direction) of the rail. The carriage includes the pair ofwing portions and a connecting portion that connects the wing portions.First raceway grooves are formed individually on the respective innersurfaces of the wing portions. Second raceway grooves corresponding inposition to the first raceway grooves are formed individually on theopposite side faces of the rail. Further, the carriage is formed havingreturn ways that are continuous with the first raceway grooves,individually. The return ways and the first and second raceway groovesconstitute an endless circulation way. The balls as the rolling elementsare held in the circulation way.

[0005] In order to enhance the stiffness of the rolling guide apparatusdescribed above, the rolling elements are held under a pre-load betweenthe first and second slide members. Conventionally, the pre-load isadjusted by selecting the size of rolling elements. More specifically, alot of types of rolling elements with different diameters-are prepared,and rolling elements with a suitable diameter are selected andincorporated into the rolling guide apparatus so that a desired pre-loadis applied to the rolling elements. In general, the diameters ofavailable rolling elements are graduated in micrometers.

[0006] Since the aforesaid conventional pre-load adjusting meansinvolves preparation of a lot of types of rolling elements, itsmanagement takes much labor. Moreover, the range of dimensions of theavailable rolling elements is limited, so that the adjustable pre-loadlevel is inevitably restricted.

BRIEF SUMMARY OF THE INVENTION

[0007] Accordingly, the object of the present invention is to provide arolling guide apparatus capable of easily adjusting a pre-load withoutbeing provided with many types of rolling elements with differentdiameters.

[0008] A rolling guide apparatus according to the present inventioncomprises: a first slide member including a pair of wing portions and aconnecting portion connecting the wing portions and formed having firstraceway grooves on the wing portions, individually; a second slidemember combined with the first slide member, movable relatively to thefirst slide member, and formed having second raceway groovescorresponding in position to the first raceway grooves, individually;rolling elements held between the first and second raceway grooves; aresidual compression stress region created on the surface region of thefirst slide member; and a worked portion formed on the residualcompression stress region on an inner or outer surface of the connectingportion and capable of deforming the connecting portion as the residualcompression stress region is worked and adjusting a pre-load on therolling elements in accordance with the deformation.

[0009] According to this invention, the pre-load on the rolling elementscan be adjusted to a desired value by simply forming the worked portionon the first slide member without preparing many types of rollingelements with different diameters that are required by conventionalapparatuses.

[0010] Preferably, the process for forming the worked portion is carriedout with the first and second slide members combined with each other.According to this invention, the pre-load can be adjusted without thetrouble of disassembling or reassembling the first and second slidemembers.

[0011] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0012] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently preferredembodiments of the invention, and together with the general descriptiongiven above and the detailed description of the preferred embodimentsgiven below, serve to explain the principles of the invention.

[0013]FIG. 1 is a cutaway front view of a rolling guide apparatusaccording to a first embodiment of the present invention;

[0014]FIG. 2 is a front view of a first slide member used in the rollingguide apparatus shown in FIG. 1;

[0015]FIG. 3 is a perspective view of the first slide member shown inFIG. 2;

[0016]FIG. 4 is a diagram showing the relation between the number ofworked portions of the slide member shown in FIG. 2 and the dynamicfrictional force of the rolling guide apparatus;

[0017]FIG. 5 is a perspective view of a slide member according to asecond embodiment of the invention;

[0018]FIG. 6 is a diagram showing the relation between the frequency ofworking on a worked portion of the slide member shown in FIG. 5 and thedynamic frictional force of the rolling guide apparatus;

[0019]FIG. 7 is a perspective view of a slide member according to athird embodiment of the invention;

[0020]FIG. 8 is a diagram showing the relation between the number ofworked portions of the slide member shown in FIG. 7 and the dynamicfrictional force of the rolling guide apparatus;

[0021]FIG. 9 is a front view schematically showing the way the slidemember of any of the foregoing embodiments is deformed;

[0022]FIG. 10 is a front view showing the way the rolling guideapparatus shown in FIG. 1 is fixed to a support member;

[0023]FIG. 11 is a diagram showing dynamic frictional forces for thecases where the rolling guide apparatus using the slide member shown inFIG. 3 is and is not fixed to the support member;

[0024]FIG. 12 is a perspective view of a slide member according to afourth embodiment of the invention;

[0025]FIG. 13 is a diagram showing the relation between the number ofworked portions of the slide member shown in FIG. 12 and the dynamicfrictional force of the rolling guide apparatus;

[0026]FIG. 14 is a front view schematically showing the way the slidemember shown in FIG. 12 is deformed;

[0027]FIG. 15 is a diagram showing dynamic frictional forces for thecases where the rolling guide apparatus using the slide member shown inFIG. 12 is and is not fixed to the support member;

[0028]FIG. 16 is a exploded perspective view of a rolling guideapparatus according to a fifth embodiment of the invention;

[0029]FIG. 17 is a front view of the rolling guide apparatus shown inFIG. 16; and

[0030]FIG. 18 is a sectional view of a rolling guide apparatus accordingto a sixth embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0031] A first embodiment of the present invention will now be describedwith reference to FIGS. 1 to 4.

[0032] A rolling guide apparatus A1 shown in FIG. 1 comprises a carriageas an example of a first slide member 1 and a rail as an example of asecond slide member 2. As shown in FIG. 2, the first slide member 1 isprovided with a pair of wing portions 11 and 12 and a connecting portion13 that connects the wing portions 11 and 12. Inner surfaces 11 a and 12a of the wing portions 11 and 12 are opposed to each other. A secondslide member 2 is interposed between the wing portions 11 and 12. Thesecond slide member 2 is penetrated by a mounting hole 14 that extendsin its thickness direction.

[0033] First raceway grooves 4 that extend in the axial direction of theslide member 1 are formed individually on the inner surfaces 11 a and 12a of the wing portions 11 and 12. Second raceway grooves 5 correspondingin position to the first raceway grooves 4 are formed individually onthe opposite side faces of the second slide member 2. The first slidemember 1 is formed having return ways 6 that are continuous with thefirst raceway grooves 4, individually. The return ways 6 and the racewaygrooves 4 and 5 constitute an endless circulation way 7. A large numberof rolling elements 8, such as steel balls, are held in the circulationway 7.

[0034] When the first and second slide members 1 and 2 relatively movein the axial direction, the rolling elements 8 between the racewaygrooves 4 and 5 roll as they endlessly circulate in the circulation way7. As the rolling elements 8 endlessly circulate in this manner, thefirst slide member 1 can smoothly move with respect to the second slidemember 2.

[0035] In the rolling guide apparatus A1, the rolling elements 8 aresubjected to a pre-load as they are elastically deformed between theraceway grooves 4 and 5. In general, there is a fixed relation betweenthe dynamic frictional force of the rolling guide apparatus and thepre-load. It is known that the higher the pre-load, the greater thedynamic frictional force is.

[0036] As indicated by hatching in FIG. 3 for ease of illustration,there is a residual compression stress region 15 on the surface regionof the first slide member 1. The residual compression stress region 15is formed of a metal structure that is impregnated with residualcompression stress by plastic working such as drawing or shot-peening,heat treatment such as quenching or tempering, or some other mechanicalor chemical treatment that is carried out in a manufacturing process forthe slide member 1.

[0037] As shown in FIG. 3, worked portions 16, which extend in the axialdirection of the slide member 1, are formed on an inner surface 1 a ofthe connecting portion 13 that is continuous with the respective innersurfaces 11 a and 12 a of the wing portions 11 and 12. The workedportions 16 are formed in a manner such that a large number of finedimples are continuously formed on the inner surface 1 a by using avibration pen P1, for example. The vibration pen P1 is a tool in which apen point of ultra-steel or the like is vibrated by means of pneumaticpressure or the like to prick a large number of fine dimples on thesurface of metal, whereby characters, lines, etc. can be inscribed onthe metal surface.

[0038]FIG. 4 shows results of determination of the relation between thenumber of worked portions 16 and the dynamic frictional force of therolling guide apparatus A1 established when the worked portions 16 wereformed on the inner surface 1 a of the slide member 1. It was found, asshown in FIG. 4, that the dynamic frictional force of the rolling guideapparatus A1 changes when the worked portions 16 are formed on the innersurface 1 a of the slide member 1. It was also found that the dynamicfrictional force decreases in inverse proportion to the number of workedportions 16. Thus, the pre-load on the rolling elements 8 can beadjusted in accordance with the number of worked portions 16.

[0039]FIG. 5 shows a slide member 1 according to a second embodiment ofthe invention. Only one worked portion 16 is formed on an inner surface1 a of the slide member 1 by using a vibration pen. The worked portion16 also extends substantially in a straight line in the axial directionof the slide member 1. FIG. 6 shows results of determination of therelation between the frequency of working and the dynamic frictionalforce of the rolling guide apparatus A1 according to the secondembodiment established when the worked portion 16 was worked a pluralityof times. As seen from FIG. 6, the dynamic frictional force decreases ininverse proportion to the frequency of working for the worked portion16, and a pre-load on rolling elements 8 can be adjusted in accordancewith the frequency of working.

[0040]FIG. 7 shows a slide member 1 according to a third embodiment ofthe invention. As an example of plastic working, in this embodiment,worked portions 16 or impressions are formed on an inner surface 1 a ofthe slide member 1 by using a punch P2. FIG. 8 shows the relationbetween the number of worked portions 16 and the dynamic frictionalforce of the rolling guide apparatus A1. It was found, as shown in FIG.8, that the dynamic frictional force decreases in inverse proportion tothe number of worked portions 16, and that a pre-load on rollingelements 8 can be adjusted in accordance with the number of workedportions 16.

[0041] If the worked portions 16 are formed on the inner surface 1 a ofthe slide member 1 by plastic working or the like, as in the cases ofthe first to third embodiments, the inner surface 1 a of the connectingportion 13 is deformed in a direction such that the distance between thewing portions 11 and 12 lengthens, as indicated by two-dot chain line L1in FIG. 9. The reason is that the formation of the worked portion(s) 16on the inner surface 1 a of the connecting portion 13 changes thecondition of the residual compression stress region 15 on the innersurface 1 a, thereby stretching the inner surface side.

[0042] When the rolling guide apparatus A1 is actually used, the slidemember 1 is fixed to a support member 20 by means of bolts or the like,as shown in FIG. 10. The support member 20 is thicker enough than theslide member 1. Normally, moreover, a surface 20 a of the support member20 that is in contact with the slide member 1 is flat.

[0043]FIG. 11 shows results of determination of the relation between thenumber of worked portions 16 and the dynamic frictional force for eachof the cases where the slide member 1 shown in FIG. 3 is and is notfixed to the support member 20. In FIG. 11, a curve C1 represents thecase where the slide member 1 is fixed to the support member 20, while acurve C2 represents the case where the slide member 1 is not fixed tothe support member 20. In the case where the slide member 1 is fixed tothe support member 20, as seen from FIG. 11, a satisfactory effect forpre-load adjustment can be maintained, although it is somewhat lowerthan in the case where the slide member 1 is not fixed to the supportmember 20.

[0044]FIG. 12 shows a slide member 1 according to a fourth embodiment ofthe invention. In this embodiment, worked portions 16 are formed on anouter surface 1 b of a connecting portion 13. FIG. 13 shows results ofdetermination of the relation between the number of worked portions 16and the dynamic frictional force of the rolling guide apparatus A1 forthe case where a plurality of worked portions 16 are formed on the outersurface 1 b by using a vibration pen.

[0045] It was found, as shown in FIG. 13, that the dynamic frictionalforce of the rolling guide apparatus Al also changes when the workedportions 16 are formed on the outer surface 1 b of the slide member 1.It was also found that the dynamic frictional force (or pre-load)increases in proportion to the number of worked portions 16. In the caseof this embodiment, the formation of the worked portions 16 changescondition of a residual compression stress region 15 on the outersurface 1 b, thereby stretching the outer surface side and shorteningthe distance between wing portions 11 and 12, as indicated by two-dotchain line L2 in FIG. 14.

[0046] If the worked portions 16 are formed on the outer surface 1 b ofthe slide member 1, as in the case of the fourth embodiment, the outersurface 1 b sometimes may be deformed relatively greatly, depending onthe position of the worked portions 16 or the working method. A supportmember 20 is thicker enough than the slide member 1, and its surface 20a that is in contact with the slide member 1 is flat. When the slidemember 1 is fixed to the support member 20, therefore, the outer surface1 b having so far been deformed is reformed into a substantially flatshape by means of the support member 20. Thus, the pre-load adjustmenteffect of the worked portions 16 cannot be maintained.

[0047]FIG. 15 shows results of determination of the relation between thenumber of worked portions 16 and the dynamic frictional force for eachof the cases where the slide member 1 shown in FIG. 12 is and is notfixed to the support member 20. In FIG. 15, a curve C3 represents thecase where the slide member 1 is fixed to the support member 20, while acurve C4 represents the case where the slide member 1 is not fixed tothe support member 20. In the case where the slide member 1 is fixed tothe support member 20, as seen from FIG. 15, there is hardly any effectfor pre-load adjustment.

[0048] In the fourth embodiment, therefore, it is advisable to form flatworked portions on the outer surface 1 b of the slide member 1 bycutting or grinding. In this case, residual stress in the residualcompression stress region 15 on the outer surface 1 b varies dependingon the volume of cuttings of the region 15, accordingly the distancebetween the wing portions 11 and 12 can be adjusted. The pre-loadadjustment effect can be maintained by fixing the outer surface 1 b,thus flattened, to the support member 20.

[0049] In order to determine the level of the pre-load on the rollingelements 8, the dynamic frictional force of the rolling guide apparatusA1 must be measured with the slide members 1 and 2 assembled together.If the worked portions 16 are formed with the one slide member 1 off theother slide member 2, therefore, assembly and disassembly of the slidemembers 1 and 2 must be repeated several times to adjust the pre-load toa desired level.

[0050] It is advisable, therefore, to form the worked portions 16 on theinner or outer surface 1 a or 1 b with the slide members 1 and 2combined with each other. In forming the worked portions 16 on the innersurface 1 a, the inner surface 1 a can be worked by means of a vibrationpen or punch that is inserted through a mounting hole 14 (shown inFIG. 1) in the other slide member 2. If the pre-load is adjusted withthe slide members 1 and 2 combined in this manner, it can be measured asthe worked portions 16 are worked without assembling or disassemblingthe slide members 1 and 2.

[0051]FIGS. 16 and 17 show a rolling guide apparatus A2 according to afifth embodiment of the invention. This apparatus A2 is provided with arail 1′ for use as a first slide member that includes a pair of wingportions 11 and 12. Raceway grooves 4 are formed on the inner surfacesof the wing portions 11 and 12, individually. A carriage 2′ for use as asecond slide member that is provided with a bearing 30 is interposedbetween the wing portions 11 and 12. The carriage 2′ is provided with apair of wing portions 31 and 32 and a connecting portion 33. Thecarriage 2′ is formed having second raceway grooves 5 and a circulationway 7. Rolling elements 8 held in the circulation way 7 endlesslycirculate in the circulation way 7 as the rail 1′ and the carriage 2′move relatively to each other. These elements are constructed in aconventional manner.

[0052] In the case of the fifth embodiment, a residual compressionstress region is formed on the respective surface regions of the rail1′, bearing 30, etc. The rolling guide apparatus A2 of the fifthembodiment is quite different from conventional rolling guideapparatuses in that worked portions are formed on an inner or outersurface 1 a or 1 b of a connecting portion 13. A pre-load on the rollingelements 8 is adjusted in a manner such that the condition of theresidual compression stress region is changed to vary the distancebetween the wing portions 11 and 12 by means of the worked portions. Inthis fifth embodiment, it is also advisable to form the worked portionswith the rail 1′ and the carriage 2′ combined with each other as thepre-load is adjusted. By doing this, the pre-load can be adjusted to itsoptimum value without assembling or disassembling the rail 1′ and thecarriage 2′. In the fifth embodiment, the worked portions may be formedon the connecting portion 33 of the bearing 30 of the carrige 2′. Sincethe bearing 30 is shorter than the rail 1′, in this case, it is easierto form the worked portions and adjust the pre-load. In thisarrangement, the carriage 2′ and the rail 1′ serve as the first andsecond slide members according to the present invention, respectively.

[0053]FIG. 18 shows a rolling guide apparatus A3 according to a sixthembodiment of the invention. In the case of this apparatus A3, acarriage 1″ for use as a first slide member makes a linear motionrelative to a rail 2″ for use as a second slide member. A pair of wingportions 11 and 12 are formed individually along the opposite side edgesof the carriage 1″ that has a substantially rectangular plane shape. Therail 2′ is interposed between the wing portions 11 and 12.

[0054] The carriage 1′ and the rail 2″ are provided with raceway members9 and 10, respectively. Rolling elements 8 or rollers are arrangedbetween raceway grooves 4 and 5 that are formed on the raceway members 9and 10, respectively. The rolling elements 8 are alternately inclined sothat the respective central axes of each two of them extend at rightangles to each other. As the carriage 1″ and the rail 2″ move relativelyto each other, the rolling elements 8 roll between the raceway members 9and 10. These elements are constructed in a conventional manner.

[0055] However, the rolling guide apparatus A3 of the sixth embodimentis quite different from conventional ones in that a residual compressionstress region and worked portions are formed on a connecting portion 13of the carriage 1″ and that a pre-load on the rolling elements 8 isadjusted by changing the distance between the wing portions 11 and 12 inaccordance with the worked portions.

[0056] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A rolling guide apparatus comprising: a firstslide member including a pair of wing portions and a connecting portionconnecting the wing portions and formed having first raceway grooves onthe wing portions, individually; a second slide member combined with thefirst slide member, movable relatively to the first slide member, andformed having second raceway grooves corresponding in position to thefirst raceway grooves, individually; rolling elements held between thefirst and second raceway grooves; a residual compression stress regioncreated on the surface region of the first slide member; and a workedportion formed on the residual compression stress region on an innersurface of the connecting portion and capable of deforming theconnecting portion as the residual compression stress region is workedand adjusting a pre-load on the rolling elements in accordance with thedeformation.
 2. A rolling guide apparatus comprising: a first slidemember including a pair of wing portions and a connecting portionconnecting the wing portions and formed having first raceway grooves onthe wing portions, individually; a second slide member combined with thefirst slide member, movable relatively to the first slide member, andformed having second raceway grooves corresponding in position to thefirst raceway grooves, individually; rolling elements held between thefirst and second raceway grooves; a residual compression stress regioncreated on the surface region of the first slide member; and a workedportion formed on the residual compression stress region on an outersurface of the connecting portion and capable of deforming theconnecting portion as the residual compression stress region is workedand adjusting a pre-load on the rolling elements in accordance with thedeformation.
 3. A rolling guide apparatus according to claim 1, whereinsaid residual compression stress region is formed of a metal structureimpregnated with residual stress by heat treatment, plastic working, orchemical treatment.
 4. A rolling guide apparatus according to claim 2,wherein said residual compression stress region is formed of a metalstructure impregnated with residual stress by heat treatment, plasticworking, or chemical treatment.
 5. A rolling guide apparatus accordingto claim 1, wherein said worked portion is obtained by plasticallydeforming a part of the inner surface of the first slide member orremoving a part of the material of the inner surface.
 6. A rolling guideapparatus according to claim 2, wherein said worked portion is obtainedby plastically deforming a part of the outer surface of the first slidemember or removing a part of the material of the outer surface.
 7. Amanufacturing method for a rolling guide apparatus, the rolling guideapparatus comprising a first slide member including a pair of wingportions and a connecting portion connecting the wing portions andformed having first raceway grooves on the wing portions, individually,a second slide member combined with the first slide member, movablerelatively to the first slide member, and formed having second racewaygrooves corresponding in position to the first raceway grooves,individually, and rolling elements held between the first and secondraceway grooves, the manufacturing method comprising: a process forcreating a residual compression stress region on the surface region ofthe first slide member; and a process for forming a worked portion onthe residual compression stress region on an inner surface or an outersurface of the connecting portion by plastic working or machining,regulating the residual compression stress region by working to deformthe connecting portion, and adjusting a pre-load on the rolling elementsin accordance with the deformation.
 8. A manufacturing method for arolling guide apparatus according to claim 7, wherein said process forforming the worked portion on the inner surface of the connectingportion is carried out with the first and second slide members combinedwith each other.
 9. A manufacturing method for a rolling guide apparatusaccording to claim 7, wherein said process for forming the workedportion on the outer surface of the connecting portion is carried outwith the first and second slide members combined with each other.
 10. Arolling guide apparatus comprising: a first slide member including apair of wing portions and a connecting portion connecting the wingportions and formed having first raceway grooves on the wing portions,individually; a second slide member combined with the first slidemember, movable relatively to the first slide member, and formed havingsecond raceway grooves corresponding in position to the first racewaygrooves, individually; rolling elements held between the first andsecond raceway grooves; a residual compression stress region created onthe surface region of the first slide member; and a worked portionformed on an inner surface of the connecting portion.
 11. A rollingguide apparatus comprising: a first slide member including a pair ofwing portions and a connecting portion connecting the wing portions andformed having first raceway grooves on the wing portions, individually;a second slide member combined with the first slide member, movablerelatively to the first slide member, and formed having second racewaygrooves corresponding in position to the first raceway grooves,individually; rolling elements held between the first and second racewaygrooves; a residual compression stress region created on the surfaceregion of the first slide member; and a worked portion formed on anouter surface of the connecting portion.